NEW Diesel Owners READ THIS

DPF Filter (Diesel Particulate or Diesel Carbon Filter)

If you have recently purchased a ‘New Generation’ Diesel powered vehicle there is something you should be aware of and it is creating a lot of misunderstanding amongst New Diesel vehicle owners. Nearly all New Generation Diesel powered vehicles are now installed with what is called a ‘DPF Filter’ in the exhaust system . click here to read more

This filter, fitted in the exhaust system, catches tiny soot particles (the black smoke you can see sometimes coming from the exhaust pipe of a Diesel engine) during engine operation and, depending on many factors, will need what is called ‘regeneration’.... or in other words a clean-out of the filter as it starts to block up. A regeneration can occur from once a day to once every few months. Factors affecting this exhaust filter clean-out can vary from stop-start city driving, poor fuel, wrong engine oil to even a slightly over oil filled engine! The regeneration cycle requires the filter to get to ‘furnace like’ temperatures of up to 1000’C as it attempts to burn off these collected soot particles. This cycle is initiated by the Engine Management Computer and is usually performed by closing down the inlet air volume and increasing the fuel mixture. Additional fuel maybe injected also. During this cycle all sorts of smells and even smoke can come from under the vehicle or engine bay as external oils and residues burn off from the outside of the DPF filter and surrounding exhaust piping due to the extreme temperature reached during filter regeneration.

Here at ‘The Diesel Experts’ we have received many calls, from distressed diesel owners, related to the DPF and these calls have generally followed over-reaction by either the owner or the vehicle dealer to these ‘scary smells and smoke’. Unfortunately by the time the search for ‘problem’ has begun, the ‘cleaning cycle’ has finished leaving everyone wondering what happened! This over-reaction to what could be called ‘the normal operation of a DPF’ has lead to costly repairs being performed due to simple misdiagnosis,  followed by a ‘bad experience feeling’ being had by the vehicles owner.  The problem is due to the lack of information and education (coming clean) on these DPF technologies by the vehicle manufacturers, which is what we try and rectify as The Diesel Experts’ through articles like this one. 

In some trucks an additional injector injects diesel fuel into the hot exhaust to assist with the ‘regeneration/cleaning cycle’. This can lead to other problems that we have seen associated with DPF issues in trucks that do many ‘stop/start’ deliveries. For example; The DPF cleaning cycle begins, as the truck is driving extra fuel is injected directly into the exhaust before the DPF to assist with the cleaning cycle. Just as the DPF begins to get hot the engine is stopped for a delivery, interrupting the cleaning cycle. The truck is re-started after the delivery and the cleaning cycle starts ‘All Over Again’. More raw fuel is injected into the DPF and before the DPF gets hot enough to burn this fuel the truck stops again for another delivery. By the end of a day of truck stop/start deliveries there can be litres of fuel in the filter and this fuel starts to literally come out the exhaust. All sorts of warning lights have come on by now and what’s next is possibly a very expensive repair.

What the long term effects this ‘exhaust filter re-generation’ may have on Engine Life will unfold with time as this technology is only relatively new to the mass-volume automotive market. Already there are very big problems and misunderstandings arising from it and its operation and hopefully through proper education and understanding this problem can neutralised.

So....remember....if you smell strong hot smells and fumes from time to time from your ‘New Generation’ Diesel ‘be aware but do not panic’. If you have a truck with a DPF filter it may be advisable to leave the engine running during the regeneration cycle until it is complete.